Merging classical music instrumentation with popular music isn’t new: E.L.O. did it successfully in the 1970s, and most recently the British group Clean Bandit last year had a chart-topping hit using classical underpinnings in its song “Rather Be.”

That doesn’t mean it isn’t a good musical technique, and Miami-based violin duo Black Violin showed at its free concert Saturday at Levitt Pavilion SteelStacks in Bethlehem that it does it very well.

And while the others merged classical with rock and pop, Black Violin -- Kevin “Kev Marcus” Sylvester and Wilner “Wil B” Baptiste – expanded the art form by playing music merged mostly with hip-hop.

Over much of an 80-minute, 18-song set, Black Violin, backed by a DJ and drummer, laid down a hip-hop beat in the style of Philadelphia’s The Roots and over it played violins that maintained classical dynamics for an interesting and entertaining show.

“We know some of you thought you were coming out to a quiet violin concert, but this is a party,” Baptiste told the packed crowd of 2,500 or so on the Levitt lawn.

That statement was a bit disingenuous. The reason the lawn was filled was because of the popular concerts the duo put on at Bethlehem’s Musikfest festival and a Levitt Pavilion show last year. (Which led to a full tour of Levitt Pavilions this year; Saturday’s show was the fifth stop.)

And Black Violin’s reputation is growing: It has played President Obama’s inauguration, on Broadway, the Billboard Awards and was a Top 5 pick at the South By Southwest festival in Austin, Texas.

But Baptiste’s sentiment was sincere: It was a party. After just a few songs, the crowd was on its feet and pressing against the stage.

As played by Black Violin, the combination of styles didn’t sound at all incongruous, as if somehow the hip-hop – even things such as the DJ’s scratching -- rose up to the classical dynamic on original instrumentals such as “A Flat Major Bach” and “Dirty Orchestra.”

The formula might have gotten repetitious had Black Violin not mixed it up as well as it did. The group sounded very much like Clean Bandit on the more pop “Animals,” and it added vocals to songs such as “End of the World,” with Baptiste singing and playing the hype man while Sylvester played, Baptiste rapping on “Sleepin’” or simply scat-singing as both played on “Virtuoso.”

The duo also expanded the boundaries of playing violin. On “The Mission,” Sylvester held the violin like a guitar and plucked its strings. And even when he used his bow, it continued to sound like a guitar. And on a cover of Imagine Dragon’s “Radio Active,” Baptiste played his violin like a mandolin or banjo.

That song and other cover songs also kept the set interesting, and also broadened the duo’s musical palate. Early in the set, it played a medley of Robin Thicke’s “Blurred Lines,” Pharrel’s “Happy,” Bruno Mars’ “Treasure” and Mark Ronson’s “Uptown Funk” – almost all of it D.J. and drums.

Later in the set, it played Sam Smith’s “Stay With Me,” with Baptiste on keyboards and singing (his vocals fell far short of Smith’s, but whose wouldn’t?) while accompanied by Sylvester on sympathetic violin, and a far more (violin-aided) hip-hop version of Wiz Khalifa’s “We Dem Boyz.”

But as if to convince the audience of its classical chops, Black Violin also played numbers that were straight-up classical, including the song that closed the main set. (In a rarity for Levitt concerts, the group actually played an encore.

But Black Violin’s true self came late in the set, when Baptiste asked the crowd, “You guys mind if we play some classical music? You mind if we spice it up a little bit? You mind if we throw some stank on it?”

It then played “Classical Train,” on which Sylvester’s playing was nicely melodic but definitely classical, and continued when it became a duet. But halfway through the song, it kicked into a hip-hop mix. It was as if Black Violin couldn’t help itself.

Black Violin will return to the SteelStacks for a show at Musikfest Café on Nov. 5, after its debut album is scheduled to be released. But that will be a paid-ticket show. Tickets, at $25-$40, are on sale at www.steelstacks.org and 610-332-3378.